Action of photoinitiator in photopolymerization system

Photoinitiator can be divided into radical photoinitiator and cationic photoinitiator. According to the different generating mechanisms of active free radicals, free radical photoinitiators can be divided into two categories: cleavage photoinitiators and hydrogen absorption photoinitiators.

With the continuous strengthening of environmental protection, waterborne photocurable coatings have been well developed. The photoinitiator used in water-based photocurable coatings also has the problem of non-water-based photoinitiator. Therefore, the development of polymer - based water - based photoinitiators is also the future development direction.

Light curing technology is a high efficiency, environmental protection, energy saving material surface treatment technology and processing technology, known as the 21st century green industrial technology. Because photoinitiator has little effect on downstream cost, the amount of addition is relatively small, there is no obvious substitution relationship between different varieties, and different products have different uses.

In the photocuring system, including UV glue, UV, paint, UV, ink, etc., the photoinitiator accepts or absorbs external energy, and then chemically changes itself and decomposes into free radicals or cations, thus initiating polymerization. Free radical photoinitiator is a kind of material which can decompose active free radicals in light to initiate free radical polymerization of polymers.

The ground state of oxygen molecule is triplet double radical. Although it cannot initiate polymerization of acrylates, it readily competes with reactions involving other free radicals. Thanks to the enhancement of people's environmental awareness and the 5E characteristics of UV curing technology, the output of photoinitiator in China has maintained a rapid growth trend.

As the main light absorbing substance, photoinitiator is the key component of photopolymerization system. The more the absorption peak of photoinitiator overlaps with the main emission band of UV-LED light source, the higher the effective radiation enhancement degree of photoinitiator.